Method of isomerizing dichlorobutenes

ABSTRACT

1,4-DICHLOROBUTENE-2 AND 3,4-DICHLOROBUTENE-1 ARE GENERALLY FORMED IN CHLORINATION OF BUTADIENE INTO DICHLOROBUTENE. Each of these isomers are useful respectively depending upon their application. 3,4-dichlorobutene-1 and 1,4-dichlorobutene-2 are mutually isomerized by reacting said dichlorobutene by using a mixture of an organic amine hydrochloride and at least one of metals and metal salt as a catalyst under a substantially anhydrous condition.

United States Patent [1 1 Kadowaki et al.

[ Dec. 16, 1975 METHOD OF ISOMERIZING DICHLOROBUTENES [73] Assignee: Denki Kagaku Kogyo Kabushiki Kaisha, Tokyo, Japan 22 Filed: Sept. 30, 1969 21 Appl. No.: 862,217

[30] Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 798,889 7/1958 United Kingdom 260/654 Primary Examiner-Leon Zitver Assistant ExaminerA Siegel Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT 1,4-dichlorobutene-2 and 3,4-dichlorobutene-l are generally formed in chlorination of butadiene into dichlorobutene. Each of these isomers are useful respec- 9 l Oct 968 Japan 43 73359 tively depending upon their application. 3,4- [52] Us CL 260/654 R dichlorobutene-l and 1,4-dichl0robutene-2 are mutu- [5 a p l I I a a a s n s s a a s l a a l s I u I u n 0 v l a n n v n 1 I I u n a 0 [58] Field of 260/654 R using a mixture of an organic amine hydrochloride I and at least one of metals and metal salt as a catalyst [56] References Cited under a substantially anhydrous condition. UNITED STATES PATENTS v 3 Claims, 1 Drawing Figure 2,328,275 8/1943 Heard, Jr. 260/654 3 a o Catalyst III .5 E Q g Ail! II C .9 .g' Q. E O 0 Catalyst I Reaction time (min) Reaction time (min) METHOD OF ISOMERIZING DICHLOROBUTENES The present invention relates to an isomerization of dichlorobutene isomers, namely, mutual isomerization between 1,4-dichlorobutene-2 and 3,4-dichlorobutene- 1 through allyl rearrangement. v

1,4-dichlorobutene-2 and 3,4-dichlorobutene-1 (abbreviated as 1,4-DCB-2 and 3,4-DCB-l hereinafter respectively) are generally formed, when dichlorobutene is produced through chlorination of butadiene. As an intermediate in production of chloroprene, 3,4- DCB-l is useful and 1,4-DCB-2 is useful as an intermediate in production of adipic acid, butenediol and the other valuable products.

The allyl rearrangement between 'l,4 DCB-2 and 3,4-DCB-1 is a reversible reaction represented by the Concerning the equilibrium composition of this reaction, British Pat. No. 569,719 discloses that the value of 3,4-DCB-1 is 30% and of 1,4-DCB-2 is 70%, British Pat. No. 798,889 discloses that the former is and the latter is 80% and Japanese Patent Application Pub lication No. ,484/68 discloses that the former is 15% and the latter is 85%.

These differences result from the difference of isomerization condition, particularly temperature but are mainly due to neglecting difference of geometrical isomers of 1,4DCB-2, that is, cis-isomer and trans-isomer.

The inventors have found that the cis-isomer and the trans-isomer are significantly different in the rate of isomerization into 3,4-DCB-l and the former is slower several times than the latter and thatthe equilibrium value of this reaction at a temperature of 80 to 120C is of 3,4-DCB-l, 7% of cis-l,4-DCB-2 and 68% of trans-1,4-DCB-2.

Dichlorobut' ene obtained by the chlorination of buta diene is mainly a mixture of 1,4-DCB-2 and 3,4 DCB-l Accordingly, in order to obtain the desired isomer, it is necessary to isomerize the other isomer. Such an object can be attained by withdrawing the desired isomer from the reaction system to disturb the equilibrium between isomers in the reaction system and effecting the isomerization repeatedly. v

An object of the present invention'is to provide 'a desired dichlorobutene in a high yield by rearranging any of dichlorobutenes, that is, 1,4-DCB-2 or 3,4-DCB 1 into the otherisomer rapidly and suppressing occur rence of side-reaction.

The isomerization reaction can be effected by heating dichlorobutene at a high temperature but in such a case a side-reaction, in which l-chlorobutadiene-1,3 and high boiling products are produced owing to decomposition, occurs; Accordingly various processes in which the isomerization is promoted and the side-reaction is suppressed, have been previously proposed and they are roughly classified as follows.

1. British Pat. No. 798,889 and Japanese Patent Application Publication No. 8,453/68;

2. US. Pat. No. 2,911,450 and Japanese Patent Application Publication No. 8,451/68.

3. German Pat. No. 1,233,385, German Pat. No.

1,235,892 and Japanese Patent Application Publication No. 484/68.

2 4. Japanese Patent Application Publication Nos.

419/66 and 420/66. 5. Japanese Patent Application Publication No.

According to the above process (1), cuprous chloride is used together with a large amount of pyridine, a-picoline or benzonitrile but when the desired product is 1,4-DCB-2, the loss of the catalyst is not negligible and the reaction rate is not rapid enough.

The above process (2) uses cuprous chloride together with hydrochloric acid or pyridine hydrochloride in the presence of water but in this process the reaction vessel is corroded by hydrochloric acid added to or by-produced in the reaction system.

The process (3) uses cuprous chloride together with an inorganic chloride, such as ammonium chloride in the presence of water or a water missible solvent but in this process the reaction rate is slow and when using water, the reaction vessel is corroded and when using a solvent, the loss of the solvent becomes serious problem.

The process (4) uses cuprous chloride deposited upon a carrier'but a significant amount of high boiling products are formed and therefore the selectivity decreases.

In the process (5), dichlorobutene is isomerized at a temperature of C in the presence of a copper compound in a vapor phase but the catalyst adsorbs high boiling products and the catalyst activity is noticeably decreased.

The present invention consists in a method for isomerizing dichlorobutene, by which the following defects encountered in the application 'of the previous processes as described above, namely,

1. The slow reaction rate, I

2. the formation of a significant amount of by-products, such as low boiling products and high boiling products owing to the decomposition,

3. the corrosion of the reaction vessel due to the presence of water, and

4. the large loss of catalyst, are solved.

The present invention comprises heating dichlorobutene at a temperature of 60 to 120C in a substantially anhydrous system by using a mixture of a metal and/or a metal salt with anorganic amine hydrochloride as a catalyst and separating the resulting dichlorobutene mixture.

The metal or metal salt applicable'to the present invention and showing excellent effects is at least one of metals and salts selected from the group consisting of metallic copper, cuprous chloride, anhydrous cupric chloride, anhydrous cupric sulfate, cupric acetate, basic copper carbonate, anhydrous ferric chloride, anhydrous aluminum chloride, titanium chloride, zinc chloride, anhydrous tin chloride and bismuth chloride.

The useful amine in the hydrochlorides includes diethylamine, triethylamine, triethanolamine, ethylenediamine, monomethylamine, dimethylamine, trimethylamine, di-n-propylamine, tributylamine, aniline, aand B- naphthylamine, diphenylamine, pand m-phenylene diamine, N,N-dimethylaniline and benzidine.

These catalysts are used under a substantially anhydrous condition and the metal or the metal salt is used in an amount of 0.01 to 10.0%, preferably 0.1 to 1.0% by weight based on dichlorbutenes to be isomerized and the organic amine hydrochloride is used in an amount of 0.01 to 5.0, preferably, 0.02 to 1.0% by weight based on the dichlorobutenes. If the amount of the catalyst used is less than the lower limits, the reaction rate is too slow and is not practical and further if these amounts are beyond the upper limits, the effect cannot be improved even by increasing the amount additionally and therefore, such amounts are not economical.

The reaction temperature is preferred to be 60 to 120C, more particularly, 80 to 100C. At a temperature lower than 60C, the reaction rate is slow and is not practical, while at a temperature higher than 120C, hydrochloric acid is separated and the decomposed product increases and further high boiling products increase and consequently the formation of the undesirable by-products is not negligible.

The present invention may be carried out in batch operation by means of a reaction vessel or a continuous operation by means of a distilling column but it is most EXAMPLES 1 17 To 100 parts of dichlorobutene mixture consisting of 2.7 parts of 3,4-DCB-1, 39.7 parts of cis-1,4-DCB-2 and 57.6 parts of trans 1 ,4-DCB-2 were added 0.5 part of cuprous chloride and 0.5 part of an amine hydrochloride as disclosed in the following Table l and the resulting mixture was fed in a reaction vessel and heated at 100C for 30 minutes to isomerize 1,4-DCB-2 into 3,4-DCB1 and then the reaction product was analyzed by gas chromatography (column Apiezon Grease-L made by Nippon Chromato Industry Company, Trade mark) to determine the amounts of 3,4- DCB-l, cis-l,4-DCB-2, trans-1,4-DCB-2 and by-products consisting of l-chlorobutadiene-1,3 and high boiling products. The obtained results are shown in the following Table 1.

Table 1 Composition of the resulting products (7:)

Example Amine in the cistrans No. hydrochloride 3 .4- 1.4- 1.4- by DCB-l DCB-2 DCB2 products 1 diethylamine 21.3 19.0 58.6 0.05 2 triethylamine 20.2 19.5 60.3 3 triethanol- 19.0 21.5 59.4

amine 4 ethylenediamine 18.7 21.1 60.0 5 monomethylamine 20.8 20.7 58.4 6 dimethylamine 23 .5 18.2 58.1 0.10 7 trimethylamine 22.8 19.5 57.6 0.05 8 di-n-propyl- 21.3 19.0 59.5

amine 9 tributylamine 23.1 17.2 59.3 0.10 10 aniline 22.5 16.3 61.1 0.05 11 a-naphthyl- 22.6 17.9 59.3 0.10

amine 12 B-naphthylamine 20.7 20.3 59.0 0.05 13 diphenylamine 21.5 20.0 58.5 14 pphenylene- 22.3 17.7 60.0

diamine 15 m-phenylene- 19.0 22.3 58.5

diamine 16 N.N-dimethyl- 19.8 23.0 57.1

aniline 17 benzidine 23 .0 16. 8 60.0

COMPARATIVE EXAMPLES 1 7 The same starting material as used in Example 1 was used and subjected to isomerization under the same condition as described in Example 1 by means of the catalyst systems as described in the following Table 2 to obtain the results as shown in the Table 2.

Table 2 Comparative Composition of the resulting products(%) Example No. Catalysts and the amounts to be used cis-l.4- trans-1,4- by- 3,4-DCB-1 DCB-2 DCB-Z products 1 Cucl 10 parts pyridine parts 15.2 36.1 48.6 0.15 2 Cucl 10 parts lbenzonitrile 30 parts 15.8 35.2 48.8 0.20 3 CuCl parts hydrochloric acid 12.2 36.7 51.0 0.15

parts water 80 parts 4 CuCl 10 parts pyridine hydrochloride 17.5 32.7 49.6 0.20

160 parts water 230 parts 5 CuuCl 10 parts NH Cl 10 parts water 10.5 36.8 52.6 0.15

parts 6 CuCl 10 parts active alumina 40 parts 17.4 32.4 50.1 0.25 7 CuCl 10 parts 51 38. 56.7 0.10

tion under an adequate reduced pressure, for example, 40 to 100 mmHg (absolute).

The invention will be further explained in detail by the following Examples. The term parts means parts by weight unless specified otherwise.

As seen from a comparison of Table 1 with Table 2, the values of 3.4-DCB-l in Table l are larger than in Table 2. Namely, it can be understood that the use of the catalysts of this invention permit one to approach the above described equilibrium value of 3,4-DCB-l of 25% more rapidly. This can be also understood from the fact that the use of the catalysts of this invention permit one to approach the above described equilibrium value of cis-1,4-DCB-2 of 7% more rapidly.

The results in the Table 2 are inferior to those in the Table l in view of a lower reaction rate and further, the catalysts in the Table 2 have the following defects.

In comparative Examples Nos. 3-5, water is used together with hydrochloric acid or amine hydrochloride, consequently, the reaction vessel iscorroded significantly. 5

In comparative Example No. 6, since porous active alumina is used as a carrier, an amount of by-products, such as high boiling products and-the like increases.

In comparative Example No. 7, there is no problem in the corrosion'of the reaction vessel and the formation of by-products, but the reaction rate is considerably slow.

EXAMPLE 18 By using 100 parts of the same starting materials as described in Example 1 and the following three catalyst systems, the variation in composition of the resulting products with time was determined.

Catalyst system I II III parts 30 parts 05 part The obtained results are shown in the attached drawing, in which the dotted lines show amounts of cis-1,4- DCB-2 and the full lines show the amounts of 3,4-DCB- I. From the figure it can be seen that the catalyst system III of the present invention allows one to approach EXAMPLES 3036 In these Examples the effect of varying of amount of diethylamine hydrochloride was tested. These tests were carried out under the same conditions as described in Example 1, except that the amounts of the amine salts was varied. The results obtained are shown in the following Table 4.

Table 4 In Example No. 36, the ratio of 3,4-DCB-l is low and the isomerization rate is insufficient, while in Example No. 30 the result is not so different from the case of less than 5 parts and therefore such an amount is not economical.

EXAMPLES 37 39 In order to determine the rate of isomerization from 3,4-DCB-l into 1,4-DCB-2 test was effected under the similar condition as described in Example 1, provided that the starting material used consisted of only pure 3,4-DCB- l. The results obtained are shown in the following Table 5.

Table 5 Composition of the resulting products ili v Ex. Amine in the cisturns the equ bnum alue more rapld y NO. hydrochloride 3.4- 1.4- 1.4- by- 1 DC B-l DCB-Z DCB-Z products 37 d' r11 1 37.0 5.6 57.2 0.20 In these Examples, the experrments were carried out 38 ii g im f in the same manner as described in Example 1, except 39 ar I 33.8 5.3 60.5 0.35 triet ano that lnstead of cuprous chloride the metal or metal salts amine 393 545 55.0 015 as shown 1n the following Table 3 were used in the same amount as described in Example 1 to obtain the results as shown in the following Table 3.

Table 3 Composition of the resulting products ('72) Example Catalyst cistrans- No. 3.4- 1.4- 1 4- by- DCB-l DCB-2 DCB-2 products 19 Fecl 18.2 25.2 56.4 0.15

(anhydrous) 20 AICI 19.0 23.8 57.1 0.10

(anhydrous) 21 Tici, 17.5 28.0 54.4 0.10 22 ZnCl 17.8 25.9 56.1 0.15 23 sncl 18.6 24.5 56.8 0.10

(anhydrous) 24 BiCl 19.5 24.1 56.2 0.15 25 Cuc1 20.5 22.3 57.1 0.05

(anhydrous) 26 CuSo, 21.0 23.6 55.3 0.05

(anhydrous) 27 cuco 01(011) 20.1 25.1 54.7 0.10 28 cmcincoo) 19.3 24.8 55.7 0.15 29 Cu 20.8 21.9 57.1 0.20

From the above Table, it can be understood that the isomerization of 3,4-DCB-l into 1,4-DCB-2 proceeds rapidly and that the concentration of cis-l,4-DCB-2 rapidly approaches its equiliblium value, that is, 7%. The latter factparticularly shows that the effect of the catalytic mixture used in the present invention is remarkable since the isomerization into cis-l,4DCB-2 is the rate-controlling step in the overall isomerization among the three isomers (See paragraph 6 of page 1 Thus it will be clear that the catalytic mixture used in the present invention shows a remarkable effect on the isomerization of 3,4-DCB-l into 1,4-DCB-2 as well as on the isomerization of 1,4-DCB-2 into 3,4-DCB-l, though the latter effect has been discussed in Examples 1-7.

What is claimed is:

1. In a method of isomerizing 3,4-dichlorobutene-l and 1,4-dichlorobutene-2 mutually, the improvement which comprises conducting said isomerization reaction by using as a catalyst, a mixture of an organic amine hydrochloride and at least one substance selected from the group consisting of copper, cuprous chloride, anhydrous cupric chloride, anhydrous cupric sulfate, cupric acetate, basic copper carbonate, anhydrous ferric chloride, anhydrous aluminum chloride,

titanium chloride, zinc chloride, anhydrous tin chloride, and bismuth chloride under substantially anhydrous conditions at a temperature of from 60 to C, wherein said organic amine hydrochloride is at least one of the hydrochlorides of an amine selected from the group consisting of diethylamine, triethylamine, triethanolamine, ethylenediamine, monomethylamine, dimethylamine, trimethylamine, di-n-propylamine, tributylamine, aniline, a -naphthylamine, B -naphthylamine, diphenylamine, p-phenylenediamine, m-phenylenediamine, N,N-dimethylaniline, and benzidine, wherein said one substance is used in an amount of from 0.01 to 10.0% by weight, based on the weight of saiddichlorobutenes to be isomerized and wherein said organic amine hydrochloride isused in anamount of from 0.01 to-5% by weight based on the weight of the dichlorobutenes to be isomerized.

2. The method as claimed in claim 16, wherein said one substance is at least one compound selected from the group consisting of cuprous chloride and anhydrous cupric chloride.

. 3. The method as claimed in claim l,'wherein said amount of organic amine hydrochloride is 0.02 to 1% by weight. 

1. IN A METHOD OF ISOMERIZING 3,4-DICHLOROBUTENE-1 AND 1,4-DICHLOROBUTENE-2 MUTUALLY, THE IMPROVEMENT WHICH COMPRISES CONDUCTING SAID ISOMERIZATION REACTION BY USING AS A CATALYST, A MIXTURE OF AN ORGANIC AMINE HYDROCHLORIDE AND AT LEAST ONE SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF COPPER, CUPROUS CHLORIDE, ANHYDROUS CUPRIC CHLORIDE, ANHYDROUS CUPRIC SULFATE, CUPRIC ACETATE, BASIC COPPER CARBONATE, ANHYDROUS FERRIC CHLORIDE, ANHYDROUS ALUMINUM CHLORIDE, TITANIUM CHLORIDE, ZINC CHLORIDE, ANHYDROUS YIN CHLORIDE, AND BISMUTH CHLORIDE UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS AT A TEMPERATURE OF FROM 60* TO 120*C, WHEREIN SAID ORGANIC AMINE HYDROCHLORIDE IS AT LEAST ONE OF THE HYDROCHLORIDES OF AN AMINE SELECTED FROM THE GROUP CONSISTING OF DIETHYLAMINE, TRIETHYLAMINE, TRIETHANOLAMINE, ETHYLELEDIAMINE, MONOMETHYLAMINE, DIMETHYLAMINE, TRIMETHYLAMINE, DI-N-PROPYLAMINE, TRIBUTYLAMINE, ANILINE, A-PHENYLEDIAMINE, M-PHENYLENEDIAMINE, DIPHENYLAMINE, P-PHENYLENDIAMINE, M-PHENYLENEDIAMINE, N,N-DIMETHYLANILINE, AND BENZIDINE, WHEREIN SAID ONE SUBSTANCE IS USED IN AN AMOUNT OF FROM 0.01 TO 10.0% BY WEIGHT, BASED ON THE WEIGHT OF SAID DICHLOROBUTENES TO BE ISOMERIZED AND WHEREIN SAID ORGANIC AMINE HYDROCHLORIDE IS USED IN AN AMOUNT OF FROM 0.01 TO 5% BY WEIGHT BASED ON THE WEIGHT OF THE DICHLOROBUTENES TO BE ISOMERIZED.
 2. The method as claimed in claim 16, wherein said one substance is at least one compound selected from the group consisting of cuprous chloride and anhydrous cupric chloride.
 3. The method as claimed in claim 1, wherein said amount of organic amine hydrochloride is 0.02 to 1% by weight. 